For example, example, Patent Document 1 discloses a conventional control apparatus for an internal combustion engine provided with a valve stop mechanism capable of keeping intake and exhaust valves in the closed position. The conventional control device performs a valve stop control so as to keep the intake and exhaust valves in the closed position in a plurality of cylinders when fuel supply is cut off, in order to suppress deterioration of a catalyst. Besides, if a negative pressure in a brake booster is equal to or lower than a predetermined value during the valve stop control, the valve stop control is released in at least one of the plurality of cylinders. In this way, an inadequate negative pressure in a surge tank (intake manifold) can be compensated for, and a negative pressure can be ensured in the brake booster.
As another example, Patent Document 2 discloses an operation control apparatus for a vehicle. The conventional operation control apparatus has a mechanism that ensures an adequate braking force for the vehicle by supplying exhaust pressure to a transformation chamber of a vacuum booster (brake booster) under operational conditions where an intake negative pressure decreases (such as during rapid acceleration or when the engine is running at high speeds).
Including the above described document, the applicant is aware of the following documents as a related art of the present invention.